Influence of various doses of aspirin (in vivo) on platelet arachidonic acid metabolism (ex vivo) and function.

The influence of various doses of enteric-coated aspirin was evaluated for its in vivo effect on ex vivo platelet arachidonic acid metabolism and function. 24 h after ingestion of the drugs compromised platelet response to the action of agonists such as epinephrine and arachidonate could be demonstrated with as low a dose as 50 mgs aspirin. However, platelets with compromised function were still capable of producing significant quantities of thromboxane. On the other hand, platelets with almost total inhibition of cyclooxygenase activity were capable of aggregating irreversibly when challenged with epinephrine and arachidonate.